This invention relates to the field of aerogels and more particularly to metal filled carbon scaffolds.
Carbon aerogels have high porosity and surface areas and therefore, are often used to create supercapacitors. Aerogel supercapacitors can have a very low impedance compared to normal supercapacitors and can absorb or produce very high peak currents. However, demand for more efficient energy storage has grown over the past few years. As a result, metals are used to fill the micro, meso, and nanoporous carbon materials (hereinafter jointly referred to as “nanoporous carbon scaffolds”). Metal filled nanoporous carbon scaffolds can also be useful for battery electrodes, hydrogen storage systems, catalyst supports, and metal matrix composites. However, there is a significant challenge in filling the nanoporous carbon scaffolds with metals as many metals do not wet well with carbon scaffolds.
Conventional processes of placing metals in carbon aerogels only result in a small amount of metal nanoparticles being incorporated within the carbon aerogels (hereinafter “aerogels” or “porous carbon scaffold”). One method of filling nanoporous carbon scaffolds with a metal involves the use of a solution of a metal precursor. Once the metal precursor is incorporated into the pores of the carbon scaffold it is then thermally decomposed or reduced. The thermal decomposition process results in voids hence, the presence of the metal in the pores is much less as compared to traditional processes of melting in or electroplating in a pure material. Other methods involve adhering carbon fibers to metal in metal matrix composites and hence are not directed toward porous carbon scaffolds having pore sizes less than 1 micron filled with metal. Another method involves the use of metal carbide compounds. In such a process, a primary metal is melted into a carbon scaffold by mixing the primary metal with a secondary metal to form metal carbide compounds. The metal carbide compounds are then reacted with the carbon scaffold. However, this method requires unwanted material to be placed in the porous carbon and also results in reaction between the secondary metal and carbon, which may damage the carbon scaffold.
Among the many demands for metal filled carbon aerogel, demand for more efficient and smaller energy storage devices has become increasing popular. Accordingly, there remains a need in the art for improved nano or mesostructured metals in a carbon scaffold, and improved processes for making the same.